Medical implants have dramatically improved the quality of life for many persons. Orthopedic devices such as total artificial hips, total artificial knees, fracture fixation plates, various fixtures, pins, wires, nails, intramedullary rods, and many others have enabled subjects to return to a high level of functioning, while restoring quality of life following debilitating diseases such as osteoarthritis, osteosarcoma, and physical trauma. Current orthopedic devices used for these and other skeletal corrections and repairs are produced in a variety of sizes to fit a range of subjects and needs. Typically the medical professional will attempt to choose the appropriate size and shape of the prosthetic device prior to surgery or intraoperatively. However, this protocol is not always successful. Often the surgeon must choose between one device that is too large, a second that is too small, and a third that is closer in size, but not quite the correct shape. Each patient has a unique need in an orthopedic device due to the infinite variation of subject anatomy combined with the infinite variation of disease and/or trauma. Although surgeons can often improvise the fit through selective removal of the subject's bone, removing otherwise healthy or undamaged tissue is not desirable, and the fit will in most cases still be less than optimal. In some cases it may be possible for the surgeon to modify the device to make a better fit, but it is not generally feasible to machine, bend, grind, drill or otherwise modify the structure of the materials used for orthopedic devices within the constraints of the operating theater. Additionally, the variety of sizes of current orthopedic devices are to accommodate different ranges of anatomical features and do not account for differences in patient activity level.
Newer methods using finite element analysis (FEA) for use in rapid prototyping have been discussed, see for example, B. V. Mehta, Annals of Biomedical Engineering, Blackwell Science, Inc., Vol. 23, S.1, 1995, pp. 9. While such methods discuss three-dimensional (3D) imaging of the implant site and design of an implantable device, their uses are limited to rapid prototyping and do not allow for the production of an actual prosthesis or usable article.
Johnson et al., U.S. Pat. No. 7,105,026, disclose a modular knee prosthesis. This prosthesis attempts to solve the problem of soft tissue balancing, which requires a surgical compromise to achieve a balance between flexion and extension gaps. Johnson et al. disclose a modular knee system having various distal posterior femoral components that are interchangeable so that the surgeon can choose the most correct compromise. Similarly, Sanford et al., U.S. Pat. No. 6,916,324, disclose a provisional orthopedic prosthesis for partially resected bone. Briefly, disclosed is a provisional orthopedic prosthesis having a first provisional component and a second optional component. The provisional component is used to assess the fit of a permanent prosthesis and is mounted on a partially prepared bone so as to allow a permanent prosthesis to be more accurately fitted. In both cases the final prostheses require an initial fitting or optimization of a generic prosthesis to achieve the fit of the permanent prosthesis.
Similarly, medical instruments are produced and manufactured in a series of standard sizes so as to best approximate the need of the users. In such cases the length, size and grip of an instrument are generally not available in custom sizes, personalized designs or custom alloy combinations. In such cases, the physician or end-user is limited to the best fit, weight or alloy available. In these cases, it would be helpful for the practitioner if there were medical instruments available that were a personalized fit for the size and grip of the user. Balance and weight of instruments may be controlled through internal features such as hollow, honeycomb, ribbed or a combination of these features. Such internal features have been difficult or impossible to produce before the advent of additive manufacturing technology which is incorporated into the invention.